Swarm
example file
This network utilizes the Property POP to give particles certain Orbit attributes which in turn are referenced by the Orbit POP. A Mass value, for example, is one of the attributes that can be assigned by the Property POP. Here, one particle is given a much greater mass hence affecting the orbiting motion of all the other lighter particles.
The greater the mass of a particle, the less other forces (including those from other particles) can influence it.
There are two particle systems in this example:
Particle system 1
The source1 POP births several particles, with a random forward velocity. The property POP gives the particles orbit attributes oaxis, oradius and ospeed. These attributes are only useful in conjunction with the Orbit POP. The orbit axis is oriented along the z-axis, with some variance. The expression rand($ID) is used to generate a random number that is unique per particle, but remains constant throughout the animation. The orbit radius also uses this expression to assign a radius between 1 and 1.5 units. The orbit speed is proportional to the orbit radius. The group1 POP groups this particle system as “light”.
Particle system 2
The source2 POP births a single particle, with a random forward velocity. The property1 POP is used to assign a mass of 20 to this particle. This is done so that when this system is combined with the first system, the center of mass will be closer to this particle. The property2 POP gives the particle an orbit axis oriented along the z-axis, an orbit radius of 1 unit, and an orbit speed of 10 RPM. The group2 POP groups this particle system as “heavy”.
The two systems are combined with the collect1 POP. The orbit1 POP makes both particle systems orbit about their combined center of mass. None of the overrides (for axis, radius and speed) are set so that the individual attributes can be used for each particle.
As the animation plays, change the mass of the heavy particle in the property1 POP to see the effect on the center of the orbit. Also try changing the Center Type setting in the orbit1 POP to Spatial or Density Center to see the effect.